Hello again, I would avoid painting over the tile at *all costs... in other words it will turn out very badly over the long term if you do so... it will not even look good in the short term.
spackling over the cracks will not help. it will just make the job look even worse.
Regarding the painting frames... only you can select paintings that you like and that will fit the space, relying on what we can do from here with photographs will work out well. All we can do is offer general principles.
Put large paintings on large wall areas, and small paintings on small wall areas.. and buy art that you like personally.. it should be high quality even if they are mass produced in China Hanging cheap or poorly done paintings does more harm than good.
In this case would buy only 3 paintings, and center them one above the couch and table, and one between the curtains. Personally I like unframed oil paintings the best. Just hang them on two level nails. You get a cleaner look that way.
It is crucial that you shop for the paintings locally, look at a hundred or more until you find something you completely like... don't settle for less... you get better art that way. Instead of paying for an expensive heavy frame you get a much larger nicer painting... I like sea scapes with sand doons, and grass myself.. lighter colored paintings, nothing heavy or dark.
The paintings should sell for between $50 and $150.. not a lot more or they might get stolen from a rental property. Shop until you find some that you really like.
Buy all wooden chairs, the sturdier the better, in a style that you like. Any furniture store will have a few dozen to choose from in a wide variety of price ranges... only you can decide which you prefer and what looks good to you in the house.
There is no way any of us, from this distance can select chairs for you.. except to provide general principles... and that is sold wood, heavily built, sturdy and that look good in the room for table chairs.
Same for easy chairs, and upholstered chairs. These are all personal taste and budget appropriate items and what matches or is a compatible fit to the other pieces of furniture. You can make those judgements ONLY by visiting a furnature show room.. thats what the show rooms are for. All good designers use the show rooms for those reasons.
, you can buy paintingson line, but in person is by far and away the best. if you go the web site that features each picture you can find hundreds more.